The cause of a fish kill on an isolated stretch of Jonathan Creek in Maggie Valley last Saturday is eluding environmental agencies and will likely remain a mystery.

A number of trout, from fingerlings to foot-long fish, turned up dead on Jonathan Creek near the confluence with Evans Cove branch in the middle of Maggie Valley.

The exact number has not been confirmed.

“I have estimates that are all over the place,” said Roger Edwards, regional supervisor of the surface water quality branch of the state Division of Water Quality.

The dead fish floating in the water were so visible it even triggered 911 calls.

Jonathan Creek is a source of drinking water for customers of the Maggie Valley Sanitary District. But whatever caused the fish kill did not jeopardize the public water source, according to Neil Carpenter, director of the Maggie water agency. Both water intakes are safely a mile and half upstream from the site of the dead fish.

“As a precaution, we sent our crews to both areas and walked the stream looking. We went a half mile above each intake and walked the stream banks and saw nothing,” Carpenter said.

While Division of Water Quality was alerted when dead fish started turning up Saturday afternoon, no one with the agency made an appearance until Monday. The nearly 48-hour lag time means anything in the water that may have contributed to the fish kill was long gone downstream. But for good measure, field teams took water samples to test things like pH and oxygen levels anyway. They did not do any biological sampling to see what kind of aquatic critters were present.

The tissue of the dead fish is not likely to unlock any secrets. For toxins to show up in tissue, fish would have to be exposed to it over a prolonged period, Edwards said.

In this case, Edwards believes there was an “isolated incident” that caused the fish kill, since the dead fish showed up during a finite window of time and a fairly short stretch of the creek.

Fish kills during summer, and especially during a summer drought, can occur when low creek levels combine with high temperatures to deplete oxygen in the water. But Edwards has ruled out that cause in this case. He doesn’t think it was sediment plume either, as that would have been visible and easy to trace to its source by eyewitnesses.